This invention relates to pharmaceutical compositions for the nasal administration of poorly water soluble drug compounds in which the drug is dissolved in a non-aqueous liquid vehicle.
The nasal route of drug delivery can afford rapid absorption of drugs into the blood circulation. In some cases absorption of almost the whole dose can be achieved and the pharmacokinetics can be similar to those achieved for intravenous administration. Such rapid and effective drug delivery can be useful in the treatment of crisis situations such as pain (including breakthrough pain and trauma pain), migraine, anxiety, convulsions, impotence and nausea.
Generally, it is preferable that compositions for the intranasal delivery of drugs are in the form of an aqueous solution. This is due to ease of manufacture, ease of delivery and good patient acceptability. However, it is not always feasible to formulate a drug as an aqueous solution, for example if the solubility of the drug in aqueous media is inadequate.
In such circumstances, one option would be to formulate the composition as a non-aqueous solution utilising solvents in which the drug has higher solubility. However, the nasal mucosal membrane is a delicate tissue and non-aqueous vehicles have a greater tendency to irritate the mucosa resulting in low acceptability to the patient. In this regard, the ideal vehicle will be odourless, tasteless and free from irritation when applied to the nasal cavity. Nasal solutions are typically delivered from spray devices that may comprise a range of glass, plastic, elastomeric and metal components. It is therefore essential that the vehicle does not interact with components of the spray device and impair the device performance, for example through sorption into plastic or elastomeric parts. It is also important that the characteristics of the liquid are such that it is atomised to form a dispersion of droplets when dispensed using a nasal spray device.